Sadly there are new cars burning that much oil or more. I wouldn't be happy with one but they're out there. As others stated check for leaks, replace the PCV valve and keep topping it up. Or if you really like the vehicle do some diagnostics, compression test, leak down test, etc. and see if it's worth fixing.
Back in 88, I bought a new Mustange with a 5.0 and a five speed (a great car) and it burned through a quart every 750 miles from new. I figured Ford just made the engine extra loose for performance sake. Eventually got 200,000 miles out of the car.
Welcome to the world of Nissan. Full of mysterious problems and rust. Going to assume it's not the head gasket. You would have noticed the oil in your reservoir. Most likely the problem originates from clogged piston oil return holes. Which causes the rings to stick eventually because oil can't be scraped off the Piston tops. Unfortunately there's no fluid that can unclog the oil control holes. Requires replacement or removal and a drill. But you may have some success slowing down the oil consumption with a piston soak. That might unjam the rings for a bit and then use a good oil to keep them free. Yes, the oil is bad for the catalytic converter long term. But don't worry about that for now. Try the soak good luck.
Thank you all for excellent advice. First thing I'll do is continue with MaxLife as I have 2 quarts remaining of the 5 gal jug. Oil was changed but I left the filter on (Fram Tough Guard good for for 15k; has 8k on it now).
I would run the maxlife, and I would definitely keep 1/2 a can of seafoam in the oil for several ocis. I have reduced oil consumption in 2 vehicles with this, and with a third am finding it or something else to be curing something I thought was piston slap.... over many, many miles.